The imperial data dump
For centuries, the city of Jingdezhen was the largest center for porcelain production in the world. Production began as early as the sixth century CE, and by the Song Dynasty (960-1279), it was a major kiln site. Emperor Zhenzong named the city Jingde after the era of his reign around 1004. The Ming Dynasty established an official Imperial Kiln Factory at Zhushan (Pearl Hill) in 1369 to produce porcelain exclusively for the court.
This imperial factory operated under a strict quality control system. Any piece with the slightest defect was smashed and buried on-site to prevent it from circulating. This policy, spanning dynasties, created enormous deposits of porcelain shards. Archaeologists have uncovered over 20 million kiln relics from these refuse piles since the 1970s. These mountains of broken pottery form a unique and detailed dataset. They are a physical record of centuries of technological development, artistic trends and industrial organization. A single order from the palace in 1433, for example, was for 443,500 pieces, all with specific dragon and phoenix designs.
Chemical fingerprints and kiln physics
The discarded shards are scientific resources. Researchers use techniques like neutron activation analysis to study the trace elements within the porcelain's clay body and glaze. The specific patterns of rare earth elements act as a chemical fingerprint. This allows scientists to identify the sources of the raw materials and detect changes in recipes over time. Analysis has confirmed that potters in different periods used different clays and production methods. Research on blue-and-white porcelain from the Yuan and Qing dynasties revealed the precise period when domestic cobalt began to be used alongside imported materials.
The kilns themselves were advanced thermal machines. Over centuries, designs evolved from dragon kilns to horseshoe-shaped mantou kilns and finally to the egg-shaped zhenyao kilns of the late Ming dynasty. These later kilns could reach temperatures over 1350°C, necessary for creating true porcelain. The shape of the kiln created a stable thermal environment, allowing for mass production of high-quality wares. The archaeology of these kiln sites reveals the material and technical basis for this massive industrial operation. Excavations uncover kiln structures and the tools and workshop layouts that show a sophisticated division of labor.